hide error if clang is not installed
hide error if clang is not installed

hiding the ugly `which: no clangi in (/usr/local/bin:/usr/bin:…)`
eigengrau/rofi,jubalh/rofi,eigengrau/rofi,jreinert/rofi,carnager/rofi,jubalh/rofi,stettberger/rofi,daemonl/rofi,jreinert/rofi,ThomasAdam/rofi,daemonl/rofi,carnager/rofi,t-wissmann/rofi,stettberger/rofi,carnager/rofi,ThomasAdam/rofi,t-wissmann/rofi